timercpu.h
Go to the documentation of this file.00001 /* 00002 * Copyright (c) 2011, Mårten Björkman (celle@csc.kth.se) 00003 * All rights reserved. 00004 * 00005 * Redistribution and use in source and binary forms, with or without 00006 * modification, are permitted provided that the following conditions are 00007 * met: 00008 * 00009 * 1.Redistributions of source code must retain the above copyright 00010 * notice, this list of conditions and the following disclaimer. 00011 * 2.Redistributions in binary form must reproduce the above 00012 * copyright notice, this list of conditions and the following 00013 * disclaimer in the documentation and/or other materials provided 00014 * with the distribution. 00015 * 3.The name of Mårten Björkman may not be used to endorse or 00016 * promote products derived from this software without specific 00017 * prior written permission. 00018 * 00019 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 00020 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 00021 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 00022 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 00023 * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 00024 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 00025 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 00026 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 00027 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 00028 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 00029 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 00030 */ 00031 00032 #ifndef TIMERCPU_H 00033 #define TIMERCPU_H 00034 00037 00038 class TimerCPU 00039 { 00040 static const int bits = 10; 00041 public: 00043 long long beg_clock; 00045 float freq; 00047 00050 TimerCPU(float freq_) : freq(freq_) { // freq = clock frequency in MHz 00051 beg_clock = getTSC(bits); 00052 } 00054 long long getTSC(int bits) { 00055 unsigned int low, high; 00056 __asm__(".byte 0x0f, 0x31" :"=a" (low), "=d" (high)); 00057 return ((long long)high<<(32-bits)) | ((long long)low>>bits); 00058 } 00059 00061 00064 float read() { 00065 long long end_clock = getTSC(bits); 00066 long long Kcycles = end_clock - beg_clock; 00067 float time = (float)(1<<bits)*Kcycles/freq/1e3; 00068 return time; 00069 } 00070 }; 00071 00072 #endif